The enormous iceberg that calved off Greenland’s Petermann Glacier Aug. 4 has split in two during its trip through the Nares Strait. Andreas Muenchow, an associate professor at the University of Delaware who has been tracking the berg via satellite images, told CNN that it broke after repeatedly running into a small rocky island called Joe Island west of Greenland.

“The forces of the ocean currents and the winds wiggling it on and off the island were too much,” Muenchow said.

The larger piece is about 152 square kilometers (59 square miles) or roughly 2.5 times the size of Manhattan. The smaller piece is about 84 kilometers (32 square miles). Muenchow and colleagues looked at historical records dating back to 1876 and determined that the original berg was the biggest to have calved off Petermann in that time.

The iceberg entered the Nares Strait, which runs between Greenland and Ellesmere Island, at the beginning of the month. A European Space Agency satellite captured its progress and the agency created this animation of the berg’s travels:

Meanwhile, Ohio State University Professor Jason Box has been thwarted in his attempts to reach the glacier to retrieve data from instruments he left last year at the site of the break. These include two time-lapse cameras that should have recorded the calving event.

He raced off last month to Greenland with colleagues in hopes of reaching the glacier and equipment. But the group was unable to arrange for a safe helicopter flight to the remote location and Box has returned home.

“Needless to say, it was difficult to turn south without the data,” he wrote Monday on his blog. He’s hoping that a flight can be arranged for one of his colleagues before mid-October when daylight becomes too scarce for such a long trip. If that proves impossible, they’ll plan on a trip in March, he said.